Francis b



(No Model.) 7

F. B. MASON. ELEGTRIG LIGHT FIXTURE.

N0. 592,805. Patented Nov. 2, 1897.

lll'l'l ll i l! W/TIVESSES. lNVE/VTOH -74; ATTORNEY.

UNITED STATES i EErcE.

PATENT FRANCIS B. MASON, OF BROOKLYN, NEW YORK, ASSIGNOR TO J. B. COLT 82; CO., OF NEW YORK, N. Y.

ELECTRIC-LIGHT FIXTURE- SPECIFICATION forming part of Letters Patent No. 592,805, dated November 2, 1897. Application filed March 19,1895. Serial No. 542,431. (No model.)

To all whom it may concern.-

Be it known that I, FRANCIS B. MASON, a British subject, and a resident of Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Electric-Light Fixtures, of which the following is a specification.

My invention relates to an improvement in electric-light fixtures, and particularly to apparatus adapted for the adjustment of the carbons of an arc-lamp by which the point of light is maintained substantially stationary, as within the focus of a fixed reflector.

I have illustrated my invention in the accompanying drawings, designating the parts by letters and referring to like parts by like letters.

Figure I is a side elevation of the lamp, showing one position of the parts in dotted lines. Fig. II is an enlarged detail view in section of one of the parts, hereinafter to be referred to as the sleeve.

A is an upright support or bar forming one part of the frame of the lamp.

(1 and O are arms suitably secured to the bar A, preferably through the holes 0 and c therein and by the set-screws c and 0 The other end of the arms 0 and O is provided with j ournal-bearings c and 0 adapted to receive the screw-shaft B. B is a screw-shaft cut with a right-hand screw-thread b on its upper half and a lefthand screw-thread b on its lower half, said screw-threads being of an even pitch. It is also provided with the hand-wheel b and the screw-threaded hole b and it is journaled, as stated, in the bearings c and 0 D is a bracket provided with a hole d at one end of a size to admit and slide upon the bar A and also with another hole at about its center, which is screw-threaded and of a size to receive the screw-shaft B. d is a collar at the other end of bracket D, provided to receive the carbon 00, which is held therein by the set-screw 01 E is a bracket substantially similar in construction to the bracket D.

e is a hole to receive the bar A, e the collar to receive the carbon 03, and e the setscrew to hold the carbon therein. The hole 6 is, however, largerthan the hole 02 and it is screw-threaded with a thread of a different pitch, this thread being of a size and pitch to receive the sleeve G, hereinafter to be referred to.

e is a screw-threaded hole to receive the set-screw g F is a stationary bracket suitably secured to the bar A. The binding-posts f and f and the reflector II are mounted on this bracket.

m and 00 are electrical connections between the binding-posts f 'and f and the carbons The brackets D and E are suitably insulated, preferably by the insulation 50 and 00 G is a sleeve. A vertical section of this sleeve is shown in Fig. II on an enlarged scale. It will be seen that this sleeve is screwthreaded on the interior with a screw-thread of of a size and pitch to fit the screw-thread b of the screw-shaft B. It is also screw-threaded on the exterior with a screw-thread of a size and pitch to fit the screw-thread of the hole 6 inv the. bracket E.

g" is a screw-threaded hole in the lower end of the sleeve G to receive a set-screw with which to fix the sleeve G to the screw-shaft B when the sleeve G is in the position shown in dotted lines in Fig. Ithat is to say, when the hole is over the hole la -and g is a hole in the upper flange of the sleeve G, which is screw-threaded to receive a set-screw. The sleeve G is fixed to the bracket E by a setscrew, as g passing through said hole g and into the hole e I prefer in the construction of the apparatus here shown that the screws '1) and b shall be right and left hand screws of equal pitch, and that the thread on the interior of the sleeve G shall be of a size and pitch to receive the screw 6 and that the pitch of the screwthread on the exterior of the sleeve G shall be one-half of the pitch of the screw b and the screw-thread on the interior of the hole 6 in the bracket E shall be of a size and pitch to means by which in an arc-lamp the light center may be maintained substantially stationary. I have observed in the use of arc-lamps that under certain conditions the position of the light center is variable. To maintain the light center stationary is important for many reasons, and it is essential where the lamp is used in connection with a stationary reflector that the light center should be maintained in the center or focus of the reflector.

In that form of arc-lamps wherein the carbons are fed to each other by operation of right and left hand screws of even pitch, such as Z) and b any variability in the consum ption of the carbonsthat is to say, should one carbon be consumed more rapidly than the otherwill cause the light center to vary in position in a direction toward the carbon which is being most rapidly consumed.

The variability in the consumption of the carbons is dependent on the character of the electric current employed. ith an alternating current the consumption of the carbons is substantially equal granted that the carbons are of equal size and quality. Vhere, however, a direct current is employed, it is found that one of the carbons is consumed much more rapidly than the other, the more rapid consumption taking place in what is called the positive carbon, which is usually the upper one, (indicated in the drawings as,

30'.) This difference in consumption I have observed to be approximately as two is to one-that is to say, the positive carbon will burn twice as fast as the negative carbon.

The object of my present invention is to provide means to compensate for such 1111-- even consumption of the carbons by arranging an adjustable feed for the same, whereby the uneven consumption of the carbons may be compensated for by such feedthat is to say, by arranging mechanism by which the carbons may be fed to each other'with a degree of speed equal to the consumption of each--to the end that the point of light may remain substantially stationary and where a fixed reflector is used in the center or focus of such reflector. The devices illustrated and described herein by which I accomplish these results operate for the purposes stated as follows: I11 Fig. I the sleeve G, as shown in solid lines, is intended to be fixed to the bracket E by the set-screw In this position the right and left hand screws 7) and operate with the movement of the hand-wheel Z) to cause the carbons to approach each other at an even rate of speed. \V here an alternating current is used with this adjustment, the consumption of the carbons will be substantially equal and the central point of light will be maintained substantiallyin the center of the fixed reflector II; but should a direct current be employed the positive carbon a" will be consu-med more rapidly than the carbon Hence the central point of light will be continually moving away from the central point or focus of the reflector as the feed is operated. To

obviate this difficulty incident to the movement of the light center when a direct cur rent is employed, I have provided the compensating feed above described, the operation of which is as follows: I first remove the carbons a: and w. I then revolve the handavhecl b in a direction to bring the brackets D and E together until the hole g is over the hole I). I then release the set-screw thus releasing the sleeve from the bracket E, and introduce a suitable set-screw into the holes g and b thus binding the sleeve G to the screwshaft I I have illustrated this position in dotted lines in Fig. I. I then revolve the hand-wheel I) in a reverse directionthat is to say, so as to separate the brackets D and E-until the bracket E has arrived at the full end of the thread on the exterior of the sleeve G, at which time the bracket D will have arrived at the full end of the screw 1). I then introduce the positive and negative carbons, the positive carbon being substantially twice the length of the negative carbon. The lamp is then in position to be operated with a direct current. As the lamp burns the positive carbon will be consumed twice as fast as the negative carbon, and it will be fed by the screw Z) twice as rapidly, and so the negative carbon a; will be consumed with half the rapidity of the carbon :0 and it will be fed by the screw on the exterior of the sleeve G with half the rapidity of the feed of the screw Z), for the reason already described that the said screws are pitched with relation to each other as one is to two. Hence the unequal consumption of the carbons will be compensated for by the unequal feed and the light center will be maintained substantially stationary and in the center of the reflector ll.

Ihave stated herein that I had observed that where a direct current is used the consumption of the carbons is unequal, as one is to two that is to say, the one carbon being consumed twice as fast as the otherand I have described my apparatus as adapted to compensate for such an uneven consrnnptimi. I do not, however, intend to confine myself to this particular adjustment. The adj ustment will be variable with different classes of carbons and currents, and it will be understood that the pitch of the screws employed must be adapted to such variations.

It will be manifest that my apparatus is readily adaptable to that form of arc-lamp described by the interposition of the sleeve G, carrying a screw-thread of such a pitch as may be necessary to compensate for the uneven consumption of the carbons.

That I claim is- 1. In an arc-lamp the combination of a pair of carbon holders or brackets with a shaft provided with right and left hand screw threads, a sleeve screw-threaded on the intcrior to fit said screwshaft, and also screwthreaded on its exterior with a thread of a different pitch, to fit a screw-thread in one of. the brackets, means to secure said sleeve to IIS either the bracket in which it fits or to the shaft, said brackets being mounted on said screws and operated thereby substantially as and for the purposes described.

2. In an arc-lamp the combination of a pair of carbon holders or brackets with a shaft provided with right and left hand screwthreads, a sleeve, screw-threaded on the interior to fit said screw-shaft, and also screwthreaded on its exterior with a thread of a different pitch, (the relative pitch of the screws of the shaft and that on the outside of the sleeve being such as to compensate for the consumption of the carbons when a direct current is employed) the said threads of a different pitch fitting a screw-thread in one of the brackets, means to secure said sleeve to either the bracket in which it fits or to the shaft, said brackets being mounted on said screws and operated therebysubstantially as and for the purposes described.

3. In an arc-lamp the combination of a frame carrying two adjustable brackets for the carbons, and a screw-shaft having a right and left hand screw-thread, a sleeve screwthrcaded on the interior to fit the screw of the shaft, and on the exterior with a thread of a different pitch and means to secure said sleeve either to the bracket or the shaft, one of said brackets having a screw-threaded hole to receive the screw-shaft, and the other a screw-threaded hole to receive the sleeve substantially as described.

l. In an arc-lamp the combination of a frame carrying two adjustable. brackets for the carbons, and a screw-shaft having right and left screw-threads, a sleeve screw-threaded on the interior to fit one screw of the shaft, and on the exterior with a thread of a different pitch adapted to cooperate with the screwthread of the shaft to compensate for the consumption of the carbons under other conditions and means tosecure said sleeve either to the bracket or the shaft, one of said brackets having a screw-threaded hole to receive the screw-shaft, and the other a screw-threaded hole to receive the sleeve substantially as described.

5. In an are-lamp in which both carbons are simultaneously fed forward into the arc, in the focus of a stationary reflector, a screwshaft provided with right and left hand screwthreads of even pitch, a sleeve provided with a screw-thread on the inside thereof, to fit the thread of the screw-shaft, and also provided on the outside with a screw-thread of a different pitch, two carbon-holders suitably mounted, one provided with a screw-threaded hole to receive the screw-shaft, and the other with a screw-threaded hole to receive the sleeve, two set-screws one adapted to secure said sleeve to the bracket, and the other to secure the sleeve to the screw-shaft, and means to operate the screw-shaft substantially as described.

6. In an arc-lamp in which both carbons are simultaneously fed forward into the arc, in the focus of a stationary reflector, a screwshaft provided with right and left hand screwthreads of even pitch, a sleeve provided with a screw thread on the inside thereof, to fit the thread of the screw-shaft, and also provided on the outside with a screw-thread of a different pitch,the relative pitch of the screws of the shaft and that on the outside of the sleeve being such as to compensate for the consumption of the carbons when a direct current is employed, two carbon-holders suitably mounted, one provided with a screwthreaded hole to receive the screw-shaft, and the other with a screw-threaded hole to receive the sleeve, and means to secure said sleeve to either the bracket or the screw-shaft, and to operate the shaft substantially as described.

Signed at New York city, in the county of New York and State of New York, this 14th day of March, A. D. 1895.

FRANCIS B. MASON.

Witnesses:

WILLIAM M. SEI'JFERT, EDWARD THURLOW. 

